Should MMOs have a 'raid stat'?

Last week, WildStar dev J-Tal outright apologized for the game's poor solo progression, stating that Carbine is "well aware that solo progression in WildStar is pretty much non-existent" and is working on the problem. But as I was researching that quote, what caught my eye is the post right after J-Tal's mea culpa, a benign little question by a player named Nike Online:

If progression is driven by need, why is there not a budget-hungry 'raid stat' that only provides benefit inside raid instances and keeps those drops more sedate when taken out into the open world? [...] PvP gear has its own stats to protect its environement from outside gear coming in and dominating. PvP power/defense also drain budget from those items so that it's not the optimal open-world gear.

Lots of games have tried PvP stats (for example, World of Warcraft's now-defunct spell penetration and resillience), but I've never seen the equivalent for raid gear. It's definitely a band-aid on a game with innate design and balance issues, but it does seem to solve the problem of overgeared raiders trampling the open world. What do you think: Should MMOs have a "raid stat"?

TH

Yeah for those who want to experience all content, it's nice that they force you to get many gear sets to just sit idle in your inventory... I'd rather have modifiable gear that has slot for the PvE stats and PvP stats so that can be avoided at least, but I aint a game dev.